This fits:

1964 Chevy ll / Nova, 4 Speed Manual Trans

1964 Chevelle, Malibu, El Camino 4 Speed Manual Trans 

1964 Impala, Biscayne, Bel Air 4 Speed Manual Trans

1964  - 1968 Olds F85 - Cutlass, 442 4 Speed Manual Trans

This Listing is for ONE (1) New Reproduction Backup Light Switch for Manual Trans cars, Part Number BU1993661.

The Switch mounts to a bracket on the side of the Transmission, this switch has been discontinued for some time now. 
If doing a concourse restoration, then this is the part for you. 
This switch was made from all new tooling and has the correct Black color water tight coating, correct color (Black & Dk. Green) bonded cable just like the original and all the correct connectors to plug into the Dash Harness or Backup Extension Harness.

This switch is one of the Best OEM Reproductions Made.